The cascading events that might lead to the end of organized nation-states in many parts of the world due to climate change look like a real possibility now.
Loss of glaciers in Himalaya ... 500 mil people on the move
Tropic & wet bulb or 50+C temperatures ... 2 mld. people on the move
Deforestations & droughts ... mass migrations, almost everybody affected
Large scale crop failures (temperatures, droughts, polinators ...) ... famines, wars
Biodiversity loses (it's critical) ... famines, huge loses for future ppl
Thermohaline circulation slow/shutdown ... cooling of northern countries, agricultural loses, extreme events
Loss of ice cover (Arctic, Greenland, Antarctic) ... rising oceans for several meters, major cities underwater
Cascading tipping points ... who knows
I'm starting to believe the sooner the system collapses, the better for the future of humanity.
Agricultural risks consolidating ag into even more megacorps.
Insurance costs making a lot of currently habitable places uninsurable, and after a few natural catastrophes nobody willing to settle in them.
Wet-bulb temperatures making the deaths of a few hundred thousands of people a frequent occurrence in many parts of the world.
Marine die-offs making the source of cheap high-quality protein in many places no longer accessible and lowering nutrition in several human populations.